Constant-potential electrical system.



DIMMITT RUSS LOVEJOY, El? IRVING'COH. NEW YGRK.

CONSTANT-POTENTIAL ELECTB-CAL SYSliEl/I.

/lfo au whom t may concern v Be it known that DIMMrrr Ross Lovn JOY, acitizen of the United State-s, residingl `at rvington, in the county of lWestchester and Stateof New York, have invented ce1'- tain new and useful Improvements in Constam-Potential Electrical Systems, ot' which the following is a specication.

My invention relates to constant potential electrical systems of' low voltage; and the objects ,of my invention are, to provide a means whereby storage batteries may be economically used as a source of current "for telephones, bells, signaling systems, etc., to l5 provide a reliable and simple means 'for keeping such batteries charged from the electric lighting circuits of the house without unnecessary use of current. and without attention, and further to provide that the higher voltage oit' the lighting system can in no case be impressed upon the low voltage apparatus and wiring, either on open or closed circuit'condition of the latter.

-I am aware that secondary batteries have been used for ringing bells, etc., and that these batteries have been charged from the lighting circuits with an interposed resistance to cut down the voltage; but this method is open to a number of objections. It involves an unnecessary and constant waste of curA ynt., an attendant is required to cut Vin the charging current. when the battery is partly exhausted and to cut oit' the current when the battery cenies up to full charge or, if the charging current is left on all of the time, the current is wasted and 4the batteries injured by prolonged overcharge; moreover, when the current is thus left on, or even when it is on only part of 40 the time, if a high resistance or a complete open circuit should occur at the battery for any reason, as by corrosion of the connections, loss of electrolyte by evaporation and electrolysis or by accidental breakage ot a battery jar, such condition being abnormal the higher voltage of the lighting circuit will be impressed upon the bell wiring, with .a consequent dangerous fire hazard on ac count' of the usualfpoor quality of such Wiring.

My inv'entikpffprovides means Wherebv the battery is aut l ically kept fully charged y Without danger o 'overcharging, under what Specification of Letters atentF Application med .my i9, isos.

. iatented Sent; 22, limsi.

serial nu. 505,504.

l will call the normal 'variations in voltage et" battery and at the same time makes it impossible for any accident, or what l will call an abnormal condition'to cause the highe' voltage to be impressed upon the low voltage circuits.

Referring to 'the drawing, which represents a complete autcmatiedevice for the accomplishing or the above enumerated ends. A and C represent electroniagnets having' many turns ot' Wire, A and C are normaliy connected in parallel with each other and across the terminals of the secondary battery l. A relatively high voltage source of direct current is indicated at D, such as an electric lighting circuit of say 120 volts. n lil represents a system of low voltage wiringand apparatus, such as electric bells, etc.

W represents an auxiliary alarm bell and battery. rilhe magnets il act upon an armature F in opposition to an adjustable spring Il, whose tension may be regulated by means ot the knurled screw l. rihe armature F is provided with a contact point J, preterably of platinum and adapted to make connection with the end of contact screw K,

also preferably tippedv with platinum, when drawn back by spring ll in opposition to thepull ot magnets A. Contact screw K is mounted at the end oi" a bar P, Said bar P being pivoted at 0 and adapted to swing downward to the position shown in the dotted outline in the drawing. Bar P is normally prevented from falling by a latch V at the end oiI armature T, said latch being released and leaving the bar P free to drop when the armature T is pulled to the lett by its magnets C. lllhen bar P drops, the opening of latch V disconnects bar P from the -lside of battery B, the point of screw l( is moved out ot' the path of contact J, and the bar P makes contact with the spring L, thus sounding the alarm W, and with the spring M, which thus short circuits the loiv tension system E. The armature F and the cores or" the magnets It are preferably made of a rather hard grade of iron so as to have considerable magnetic hysteresis. This is necessary to secure a posit-ive opening and closing of the contacts J, K, and this etlect of hysteresis is assisted by the change -in length of the air'gaps when armature F approaches or recedes trein the poles of maximum. length is adjusted by means et the contact screw K. A ground connection is shown at (l, it being assumed that the negative side et the lighting circuit is grounded. rThe other connections are as shown in the drawing.

The operation ot the device is as follows: lV hen the apparatus is set up and the connections made. as shown, the battery ll being uncharged, the magnets A. and C are not energized, and their respective armatures are both pulled back by the springs -as shown in the drawing. Current then flows lrom source D, through resistance l, (said resistancebeing ot a value depending upon the size and current demand ot' the system Emili most cases ,lt will be about GOOolnns ivhere D is of l2() volts) 'thence through pivot X and armature l? to Contact J, K, thence through latch V to armature 'l' sind to the -l side of battery B, and 'trom the side of battery back to side et source D. The tension of spring il is thon adjusted so that when battery B is up to normal voltage, say about. `volts per cell, the magnets XL will `iust he able to overcome spring H, pull the armature over, open contacts J, K, and interrupt the charging current. When armature l? starts to more, it will go all the Way until it strikes the stop Q; on account of the shortening ot the air gaps by the approach of the said arnuuure to themagnet poles,A and.r on account ot hysteresis and this shortening, it will be held even after the voltage of the battery has fallen through use, since the magnetism of the hard iron will not decrease as fast as the magnetizingcurrentin the coils and consequehitly the charging current Will be kept oit until the voltage of the battery has fallen considerably. VVhenthis has taken place however, the iron will have de.- magnetized sutliciently for the spring- H to overcome the magnetic pull, draw the armature back, cut in the contacts J, K.' and again start the charging current. New, on account of hysteresis and the lengthencd air gaps, the magnetism ot the cores will build up more slowly than the voltage of the battery and the magnetizing current depend ent thereon, and time will @lapse betore the magnet is again able to overcome the spring H and again open the contacts J. K. The adjustment of the screw K and of the spring H will determine the voltage at Which the armature is drawn overtowill be in stable condition when the contacts el, K a re either open or closed, and so Vibration or chattering of the armature will not occur and the battery will be automatically connected and disconnected to and from the charging source so as normally to keep its charge up to substantially full normal voltage.

The magnets C are Wound with finer wire than those of A., or the air gaps interven-A ing between said magnets and armature T are longer, or both, so that when the battery is up to full voltage, the said magnets (l are still unable to pull the armature T and unlatoh V., and consequently this part ot the device does notoperate under what I have called normal conditions.

rlhc battery being connected across the terminals of the Working circuit E, the voltage impressed thereon cannot vexceed that of the battery so long as the battery is in order. It however, the battery should becoine open circuited in any way as hereinbefore pointed out, then, when' the contacts J', K are closed. the full voltage of 'D would be impressed upon the system E und upon both magnets A and C. To prevent anything more than a moderate rise of voltage on E, the adjustment of magnets C is such that the armature T will be attracted whenever a voltage of say 50% or 100% above normal of the battery is reached, this voltbeing still` much lower than that of the source D, and not vet reaching a `value dangerous to E. l.When this happens, the latch lf is opened, the. bar P is released and drops down into the position shown by the dott-ed outline in the drawing and closesithe' auxiliary alarm contact L and at the same time moves screw K out of range of'contact J and so entirely cntsout the side of the high potential D. urthermore, bar P also closes eontact'M and short circuits the working `circuit E, thus insuring beyond any doubt that there can be no ris of voltage upon said system E.' The armatures T and F will both fall back against the common stop U as both magnet windings will be Without current. The closing of contact L starts the alarm W and at once calls attention to the fact that there is something Wrong and, when this is' attended to. the device is re-set by lifting bar P back by hand/until it again locks in its normal posiis preferably pro' tion. The armature F A storage battery, a low tension Working c c f vided with a Weight r, to increas ment of inertia so that when an s rise of voltage tenes place, the armature L will move quicker than open the litten V before arcing can occur at the contacts J, K. There will oi'- course occur a nio- Inentary moderate rise Voltage on the above'action takes place but, as he' pointed out, the amount of' this clone. rise of Voltage is limited loy the adjust-nient of magnets C intl armature )il so as to opcrate the cut out device betere the rise of .foltage on E can reach a. value suthciently high to he dangerous thereto, snol after the cutout has operated there will he no voltage Whatever impressed on E. The armature 'LT is purposely made light and quick ect-ing as to respond instantly when the volta starts to rises l. A low potential system comprising cuit, a relatively high 'potentiel source ci charging current for battery. resistance for controlling sani. charging cnent, and means for automatically short circuiting said working circuit when the Voltage across terminals rises abnormally.;

2. A low potential syste-'in con'grisine; Working circuit, a Storal battery, a relatively high potential source ot o erging' ci rent, resistance for controlling hharginoj current, and means or autonieticel i f sconnecting said source and. said working cuit from said battery anti` for short circuiting' said wor ing circuit when the voltage across its terminals abnormally.

3. A low potential system comprising a working circuit, a storage battery, a rele.- tively high 'potential source of charging; cnrrent, resistance for controlling said charging` current, and means for automatically connecting said source and sairl Working circuit from said battery and short circuiting said Working' circuit and for sounding an alarm when the voltage across the terminals of sairl battery and Working circuit rises rronormally,

el. A low potential system comprising a storage battery7 a relatively high poten source of current, resistance or controlling said charging current, means for automatically connecting and disconnecting said source to and from said battery under i ormai variations in Vvoltage ofsairl battery', said means acting` relatively' slowly, and additional means for automatically tlisconnecting' seid source from said battery when the voltage across its terminals rises to a value alcove the fully charged Voltage of said hatterv. saifl additional means acting relativffli7 cnicsiy by reason of any abnormal contri tion.

low potential system cornpfing a working circuit, a storage battery, a rela working circuit, a, storage battery, a relel tively high potential source of charging current, resistance for controlling said. charging current, means for automatically connecting and disconnecting saicl source to end from saicl battery under normal variations i'. voltage of said battery, enclnrnea-ns for antoinatically di 'connecting saitl source and ssicl Working circuit :trein said battery and for short circiiiting' Working circuit when the voltage their terminals rises abnormally.

"e". il. low' potential system comprising Working circuit, storage hattery, rele,- tivcly high pot source charging cnrrent, resistance Y rolling said charging current, means for an tically connecting anti disconnecting source to 'troni said battery uncle: normal variations in voltage of said. hatt J, and means for auto niatically (lisconnec aicl source and Working; cir/snit frein battery and for short circuitin?,` said Working circuit and tor sounding en alare when the voltage across the. terminals cl Working circuit rises ahi'iornnilly.

8. in low teneis iystein, the combination with low ten "o Working circuit and a low tension storage battery shouted across saitl circuit, ot relatively high tension source of charging current for said battery, series resistance tor 'eclncing the voltage ot' sai hi 5h tension source hy ohmic drop, and automatic means for preventing said higi voltage 'from being impressecl upon saitl working circuit in case of an abnormally high resistance in seid shuntecl hz 'ry circuit, sairi automatic ineens being atlaoefl operate on a relatively nali rise of mittags above the toll einD 'ge Voltage of saicl battery, and saifl automatic ineens acting relatively quickly.

9. A low potential system comprising a. storage battery, a rela .ively high tension source of charging cum-ent for said battery, resistance for limiting seid charging current, a Working circuit connected across the terminals ot seid battery, an electromagnet and an armature therefor having jointly a slower rate ci' time response and connected in par allel with said Working circuit and having an armature adapted to control the opening source to saidL hotti clectroinegnet anni ery, and an additional iature having jointly a quicken? rate time respons-e also Qonbatt y t worhng circuit, :for the nected m parallel mth sani Wormo @.rcult pulpos@ of proie-sting said Working circuit than the, magnet and armature having me slower time rate and, in so espondjng, o` permanently open tha respective circuits connecting Said battery ilo said source and DIMMITT R SS LOVEJOY. Witness-as JAS. J., EmiENmmi-I, M. V. GELSEN..

and adapted to resp/and to a higher voltage l against my abnormal :.se of votage. 

